Motion picture encoding device and motion picture decoding device

Abstract

When a prediction is made between fields with different parity, the predicative efficiency of a chrominance vector is improved by adaptively switching the generation of a chrominance motion vector depending on a encoding/decoding field parity (top/bottom) and a reference field parity (top/bottom), and the coding efficiency is improved accordingly.

1. A motion picture decoding method comprising:
 decoding, by a decoder, a motion picture signal composed of a top field and a bottom field and encoded with inter-field motion compensating prediction, each field formed in a 4:2:0 picture format, said decoding comprising:
 generating a chrominance motion vector from a luminance motion vector of the encoded motion picture signal according to a respective calculation method adaptively selected from a plurality of different calculation methods depending on parities of a coding field, which is one of the top field and the bottom field, and a reference field, which is one of the top field and the bottom field, of the encoded motion picture signal, wherein a first calculation method is employed for generating the chrominance motion vector from the luminance motion vector when both the coding and reference fields are the top fields or the bottom fields, a second calculation method is employed for generating the chrominance motion vector from the luminance motion vector when the reference field is the top field and the coding field is the bottom field and a third calculation method is employed for generating the chrominance motion vector from the luminance motion vector when the reference field is the bottom field and the coding field is the top field. 
 
 
     
     
       2. A motion picture decoding device comprising:
 means for decoding a motion picture signal composed of a top field and a bottom field and encoded with inter-field motion compensating prediction, each field formed in a 4:2:0 picture format, said means for decoding comprising:
 means for providing a luminance motion vector of the encoded motion picture signal; and 
 generation means for generating a chrominance motion vector from the luminance motion vector according to a respective calculation method adaptively selected from a plurality of different calculation methods depending on parities of a reference field, which is one of the top field and the bottom field, and a coding field, which is one of the top field and the bottom field, of the encoded motion picture signal, wherein the generation means generates the chrominance motion vector from the luminance motion vector by employing a first calculation method when both the reference and coding fields are the top fields or the bottom fields, by employing a second calculation method when the reference field is the top field and the coding field is the bottom field and by employing a third calculation method when the reference field is the bottom field and the coding field is the top field. 
 
 
     
     
       3. A motion picture decoding device comprising:
 a decoder decoding a motion picture signal composed of a top field and a bottom field and encoded with inter-field motion compensating prediction, each field formed in a 4:2:0 picture format, the decoder comprising:
 a unit providing a luminance motion vector of the encoded motion picture signal; and 
 a generator generating a chrominance motion vector from the provided luminance motion vector according to a respective calculation method adaptively selected from a plurality of different calculation methods depending on parities of a reference field, which is one of the top field and the bottom field, and a coding field, which is one of the top field and the bottom field, of the encoded motion picture signal, wherein the generator generates the chrominance motion vector from the luminance motion vector by employing a first calculation method when both the reference and coding fields are the top fields or the bottom fields, by employing a second calculation method when the reference field is the top field and the coding field is the bottom field and by employing a third calculation method when the reference field is the bottom field and the coding field is the top field. 
 
 
     
     
       4. A method comprising:
 decoding, by a decoder, a motion picture signal composed of a top field and a bottom field and encoded with inter-field motion compensating prediction, each field being formed in a 4:2:0 picture format, wherein a location pattern of pixels of a chrominance component and a luminance component in the top field is different from that in the bottom field, said decoding comprising: 
 generating a chrominance motion vector from a luminance motion vector of the motion picture signal according to a respective calculation method adaptively selected from a plurality of different calculation methods depending on parity between a reference field, which is one of the top field and the bottom field, and a coding field, which is one of the top field and the bottom field, of the motion picture signal, wherein a first calculation method is employed for generating the chrominance motion vector from the luminance motion vector when both the coding and reference fields are the top fields or the bottom fields, a second calculation method is employed for generating the chrominance motion vector from the luminance motion vector when the reference field is the top field and the coding field is the bottom field and a third calculation method is employed for generating the chrominance motion vector from the luminance motion vector when the reference field is the bottom field and the coding field is the top field. 
 
     
     
       5. An apparatus comprising:
 means for decoding a motion picture signal composed of a top field and a bottom field and encoded with inter-field motion compensating prediction, each filed being formed in 4:2:0 picture format, wherein a location pattern of pixels of a chrominance component and a luminance component in the top field is different from that in the bottom field, said means for decoding comprising: 
 means for generating a chrominance motion vector from a luminance motion vector of the motion picture signal according to a respective calculation method adaptively selected from a plurality of different calculation methods depending on parity between a reference field, which is one of the top field and the bottom field, and a coding field, which is one of the top field and the bottom field, of the motion picture signal, wherein the means for generating generates the chrominance motion vector from the luminance motion vector by employing a first calculation method when both the reference and coding fields are the top fields or the bottom fields, by employing a second calculation method when the reference field is the top field and the coding field is the bottom field and by employing a third calculation method when the reference field is the bottom field and the coding field is the top field.